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Is it possible to become a commerical pilot and have an Emotional Support Animal?
I was wondering this as I am trying to get an ESA while also trying to get my pilots license. I was wondering if this will interfere with my plans to becoming a pilot.

Needing an emotional support animal may indicate a disqualifying mental health condition.

Even if you could get a license, there'd be almost no air carrier that would allow it.

There was a post on here about this a couple of years ago, by someone who'd faked a problem to be able to take her pet on airline flights using the ESA rules, and now she wanted to get a pilot license and was going to have to disclose her "fake" psychological condition. A tangled web she wove for sure.  Assuming your problem is legit, it's still likely to be a problem as emotional or psychological issues are generally disqualifying, so think hard about whether an ESA is really necessary.  But check with a medical examiner.

@JohnK This thread is the one you're referring to. Not quite a dupe, but interesting reading. Wonder how that case turned out...

I'm going to be blunt, and it is both for your own and the good of the general public: if you have a mental condition that requires an emotional support animal to accompany you through your normal daily tasks, you are not fit for a professional pilot job.

While you mentioned being in the process of obtaining both, there are actually two different questions implied:  1. If I have been diagnosed with a mental condition requiring an ESA, will that disqualify me from a commercial pilot certificate?  2. Can I reasonably expect an air carrier to allow me to bring my ESA along while I am flying for compensation?  The answers may be different.

... looking at it again I see a third possible interpretation from the wording of the title question:  3.  Can an ESA be a commercial pilot?  The answer to that one is a definite no.

@RalphJ oh yeah! That was to get around a rental property no-pets rule.  She didn't get much sympathy for her cynical motives in the comments lol.

@JohnK  She really didn't! If there was ever going to be a tough crowd for sympathy for somebody who (in her case, not the OP here) claimed a fake emotional support animal, airline pilots, flight attendants, & frequent fliers would be it. We saw so many pets that flew (the rule has changed a bit recently) free because nobody could question the emotional support status of Fluffy, that we got pretty jaded. Which hurt those with a legit need and an actual emotional support animal.  I think "hoisted on her own petard" was the chuckled commentary on her situation there!

Welcome to aviation.SE! Which country’s regulations are you asking about? Although, even if your country’s medical regulations allow it, it would probably be very impractical.

@MichaelHall your 3rd option is the first way I read it! "Let's eat Grandma!" Commas save lives.

The ESA animal should be a gerbil.  Very easy to (ahem) hide.

There’s no reason you can’t that I can think of. That being said, if you need an emotional support animal for day-to-day life, you may not be able to handle the stresses of flying, emergencies, etc.  And they are not gonna let you keep a dog or similar critter in the cockpit with you.

While I totally agree with your answer, “no reason I can think of” falls short of the sort of credibility this site craves.  Most medical questions here are quickly dispensed of with recommendations to seek out an AME or other medical professional.  Just an observation FWIW…

I dunno, the first sentence is a problem.  He has to check a box about mental issues "of any kind" on the medical form that he has to sign, on penalty of fines and jail time.  Emotional sensitivity or instability requiring an animal will almost certainly be disqualifying if the condition is current as  opposed to "recovered from".  If he's a vet that needs it because of PTSD, that's a real shame.

Your first sentence and the rest of your answer seem to be contradictory...

Obtaining an ESA is not against any kind of medical requirement needed for a flight physical. Now if this was prescribed by a doctor as part of a diagnosis for another mental condition, yeah I could see that.

To get an ESA with the right to take that ESA wherever you want, which is the point, you have to have a diagnosed condition.  If you have a diagnosed condition, you have to check the box on the medical form.

If a mental condition requires an ESA, it would likely disqualify an applicant from obtaining an aviation medical clearance.

“If” the reason for an ESA is a disqualifying medical condition.  This is not always the case.  People can get ESAs simply because they feel sad and lonely

@JohnK Not sure what OP's jurisdiction is, but ESAs and service animals are completely different under U.S. law. The legal right to take them wherever you want only applies to actual service animals, not ESAs. The only extra legal right for those is to have one in your home, even if your landlord bans pets.


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What is the origin of the term "Tyro" for inexperienced pilots?
Over the years I have been aware of the term "Tyro" to mean a new or inexperienced pilot. I'm pretty sure it is/was used more in a military setting than a GA one, but none the less I was interested to know if anyone knows the origin of this term, and the reason why it is used? Is it still used commonly?
This may be a term only used in the RAF, I don't know.

It's a portmanteau word for "tires, zero".  As in, on an inventory of the intact undamaged parts remaining on the aircraft after the end of a flight.

It's just a synonym of novice, it is used outside of aviation. Like many other aviation terms (e.g. pilot) its origins precede the first manned flight and it was and is used for non-aviation novices. Aviators borrowed many existing terms.
tyro (n.)
1610s, from Medieval Latin tyro, variant of Latin tiro (plural tirones)
"young soldier, recruit, beginner," of unknown origin.

http://www.etymonline.com/index.php?term=tyro

Ok, thats good. The "google" answer. But when, and why was this applied to pilots?

@Jamiec: From ngrams I'd expect it to have been used the day after the Wright brothers started calling themselves air pilots (compared with river pilots?)

I think your edit makes this a much clearer answer. Thanks.

Tyro doesn't get much usage these days outside of two real areas: pilot jargon and wizard's apprentices.

@corsiKa: ... and football and karting and lifeguards and offroading and bloggers and ...

For evidence of active usage, check out @Simon's comment on the accepted answer to this question, in which he uses the term "tyro."

How derogatory is "tyro"? Would you refer to yourself as one on radio, or is it a pejorative ATCs would mumble under their breath with the mike off, like "noob"?

@KeithS At least in the UK, it's recognised terminology and is not pejorative at all.  I would call "blah blah control, Finden 37 tyro, request blah blah".  It was brought into use after a 16 year old student on his second solo crashed and died whilst trying to deal with some (relatively) complex ATC instructions after being told to break off an approach. The idea is that ATC will issue simpler instructions such as "cancel clearance, fly North".

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What are the different variants of ILS intrumentation?
Background: I'm a huge aviation enthusiast with a lapsed PPL. Have flown some larger aircraft on MSFS, but never flown anything in real life bigger than a C172.
I was lucky enough to do a bit of Simulator time on a B737 simulator this weekend. One thing I wanted to try out was an ILS approach in very limited visibility. The instructor set me up, and asked what ILS display I was "used to seeing". I described it, and she set it to this - totally what I was expecting:

(Thats the purple vertical bar for centre line and purple blip for glide slope).
So, my question is, what was the "Other" option? This may be specific for a B737, or it may not. Why are there 2 types of instrumentation for an ILS approach? Is one a newer system, and is it therefore preferred.

In the Boeing next-generation "NG" flight decks, the PFD can be configured one of two ways. The first way, is the default presentation, where you only see to top of the HSI. The pilot will fly the aircraft via the pips along the bottom and right of the attitude indication (and usually with the flight director cross as well):

If my memory is correct, Boeing, NASA, and others did a number of human factors studies over the years and found that this layout allowed pilots to more quickly understand critical flight information, and this layout is now standard even in GA glass cockpits (e.g. Garmin G1000, Collins Proline).
The second configuration provides a virtual "six-pack":

This configuration is primarily used for airlines that are transitioning between "Classic" and "NG" flight decks. One airline I remember in particular is Southwest, as they had a combination of 737-300/400 and -700/800 aircraft and having a classic configuration on their new flight decks allowed all of their pilots to fly any of the aircraft, without needing significant differences training. The particular presentation can be customized per the airline's needs. An airline will typically move exclusively to the modern PFD display once all of the older aircraft are moved out of the fleet.

That would be the double needle display. Here are the 3 most common displays:

source
The one on the left is the one you are used to.
the one in the middle is the classic double needle design where each line pivots on the point at the top or on the left. The one on the right is equivalent to the one in the middle except that the bars don't rotate but just move up and down and left and right.

Thanks ratchetfreek, as per question is one system newer? Are any the preferred system or just pilot preference?

I wouldn't expect B737 to ever show the right two options. Either HSI or the indicators around PFD (they do work similar to the right one, true).

... or flight director, of course.

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How do you perform a gear-up landing in a large airliner?
How do you perform a gear-up landing in a large airliner (say, a Boeing 747)?  Would you fly it like a normal landing, or are there special considerations (angle of touchdown, use/non-use of thrust reversers, etc.)?

It was a small GA plane, but this pilot told ATC to "tell my wife I love her."

Patrick Smith, a US pilot, examines the issue in his book Cockpit Confidential http://www.amazon.in/Cockpit-Confidential-Everything-Questions-Reflections-ebook/dp/B00C69H7RC

It recently happened to LOT B767 in Warsaw; the landing went quite well.

Assuming that the pilots have tried everything possible and the gear just does not like to come down:
The general rule is to find a long runway, touch down as slow as possible. Here are sections extracted from Boeing 777's Flight Crew Training Manual:
Dumping fuel

If time and conditions permit, reduce weight as much as possible by burning off or jettisoning fuel to attain the slowest possible touchdown speed.

Elevator

After touchdown lower the nose gently before losing elevator effectiveness.

Rudder

At touchdown speed, the rudder has sufficient authority to provide directional control in most configurations.

Speedbrakes

(...) speedbrakes should be extended only when stopping distance is critical. Extending the speedbrakes (...) may compromise controllability of the airplane.

Reverse Thrust

(...) an engine making ground contact could suffer sufficient damage such that the reverse mechanism may not operate. Selecting reverse thrust (...) may produce an additional asymmetric condition that makes directional control more difficult. Reverse thrust should be used only when stopping distance is critical.

Landing technique
The technique varies with the combination of failure. If one side of the main gears is missing, land the plane to the side of runway which corresponds to the extended main gear. I.e. if the left gear is down and right gear is up, land on the left side of the runway instead of centerline. Maintain wings level for as long as possible, and be prepared to brake on the left side to maintain directional control.
If all the gears decide to hide in the gears bay, land on centerline and use rudder to maintain directional control. Rudder is effective until airspeed drops too low.
After landing
Evacuate the aircraft as necessary!

Would it be a bad idea to retract the left gear/nose gear again, if possible? Maybe it would make it easier for the pilot to maintain directional-control and puts the load on the center-body, instead on the right wing. PS: Execluding B747/A380 and so on, they have more than two main-gears.


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Why are piggyback launches done by dropping the carried aircraft and not by "fly-off" launches?
Every air-launched aircraft I'm aware of, with the exception of the D-21 in combination with the M-21 carrier, has been launched by dropping it. Is there a reason why drop launches are preferred to "fly-off" launches from the top of the carrier?

I guess flyoff require some engine power from child aircraft which might affect flying characteristic of parent aircraft. Hence fall-off then ignite is more preferable.

Remember how the Shuttle glider was launched from a 747? All it takes is a zero-g maneuver called a parabola. By the way, this is also the preferred way to bail out from a high-performance aircraft without an ejection seat. Trim full nose-down but pull to keep the flightpath level, open canopy and seat buckle, and just let go of the stick.

glider ... presumably the struts can't take it spooling up, and the 747 isn't going to like getting torched, and it didn't have any fuel anyway. affect flying characteristic is why the Anton had two tails.

Its much safer, you don't kill the carrier aircraft if you drop away and have a major aircraft malfunction.  Gravity gives you the separation you need.
If you treat the two aircraft like a formation flight, which it essentially is, its dangerous for the critical aircraft to go belly up, ie blind, to the carrier.  In an emergency the first step in formation flying is to ensure separation which the critical aircraft can't do because it can't see if it's clear to descend and it may not have the ability to laterally sidestep.  Thus, a blind push on the nose could kill both aircrews.

The test launches of the space shuttle (both US and USSR) were top launches. (though that was due to bulk more than aerodynamic considerations)

Drop launches get you out of the wake of the carrier faster and it is easier to get vertical separation by dropping than by climbing.
With fly-off you start in the turbulent area and then need to get enough speed to fly, and stay in front or above of the launching craft until flight has stabilized.

Also, with fly-off, you're pointing your engines straight at the plane you just took off from, as soon as you start to climb: that could presumably be problematic.

And you are dangerously close to the tail !

@Antzi - Speaking of that, since the shuttle was unpowered, how did it manage to lift off from the carrier aircraft without drifting back into the tail? I always thought that when you pull back on the stick to climb, you gain altitude at the expense of speed.

@Johnny I have no idea, maybe the plane used its air brakes while the shuttle was gliding

@Johnny My guess is the carrier aircraft pitched aggressively nose down to avoid collision after detachment.

There's video of the shuttle glide tests here: https://www.youtube.com/watch?v=v-YNcwc1ZME; the shuttle separates at around the 4:35 mark.

If the plane is up the carrier and something go wrong, both planes crash. The first test of the USA Space Shuttle were done with a carrier having the shuttle on its top; it was for wind tests. A carrier having a plane to drop of a plane to take off from a carrier was tries to reach space at lower cost, planned in the 1970s and the tests done in the 1980s. A model with reservoir was chosen instead.


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What is the difference between being instructed to land "as soon as possible" or "at nearest suitable airport"?
On commercial airliners, the FCOM (Flight Crew Operating Manual) sometimes gives instructions to the pilots to land sooner than planned, following various in-flight failures or emergencies. For instance, for serious emergencies (e.g. in-flight fire), the pilots would be instructed to LAND ASAP (as soon as possible), as there is a real danger to the aircraft and its occupants if they stay in the air any longer.
For less severe situations, the pilots would be instructed to LAND ANSA (at nearest suitable airport), which gives them more leeway in deciding where to land.
My question is: other than the fact that LAND ASAP is obviously more urgent than LAND ANSA, could anyone go into more details as to how a pilot would interpret these instructions, and how they differ? (for instance, does LAND ASAP mean "land on the nearest reasonably smooth surface", or is it less extreme than that? Are there guidelines on approximately how long you should keep flying after receiving a LAND ANSA instruction?)

In the planes I fly, ASAP means pick the open field in your vicinity which is least likely to kill you and land there. Don't know this applies to airliners though. :)

I would interpret them as:
ASAP means the plane is going to kill you. Soon. So land before that happens. Short runways, military airports, abandoned airfields, a decent highway, dry lakes (e.g. Edwards AFB), calm bodies of water (e.g. the Hudson River) are all possibilities. Do not concern yourself with operational issues like taking off again, and bureaucratic formalities like immigration will be summarily ignored. Obviously if you are near the Hudson you would try very, very hard to reach JFK, Teterboro or Newark, but sometimes that doesn't work out.
ANSA means try for a real airport considering immediate operational and bureaucratic requirements, but not beyond immediate. this could include turning around and landing at Goose Bay. Basically I'm going to punch "Nearest" on the Nav panel and make an educated choice. Most Nav sets will only show open airfields that can accommodate your aircraft. For example, Gimli would not have appeared for Air Canada flight 143, assuming they had a suitable unit back then and the power hadn't gone out.
The terms are deliberately unclear to give the pilot some flexibility - you can't predict and write a procedure for everything.

Land ASAP means a controlled landing, dont confuse this with a forced landing.  In other words, the pilot still has a choice of where and when, and will always choose a suitable runway over the Hudson river.  Downvoted for this.

@MichaelHall: A forced landing is a controlled landing.  An uncontrolled "landing" is known as a "crash".

Good point Sean, I just meant that the airplane can fly to a suitable airfield.  I.e., it isn't a glider as it is in a forced landing.

LAND IMMEDIATELY
Continued Flight may be more hazardous than Ditching or Forced Landing
LASAP
Land as soon as possible at which a safe landing can be made or is assured
ANSA
Land at nearest suitable approved airport
Land as soon as Practical
Extended flight not recommended. Landing airfield and duration of flight are at the discretion of the pilot. Extended flight beyond approved landing airport is not recommended

I don't see how this answers the question, so much as providing more terms which may (in some unknown context) be synonymous with the terms in the OP, or which may be more gradations between extreme and slight urgency.

You may add an introduction sentence to explain how it answers the question (something like "it depends on how such ans such criteria. Moreover other terms exists")

Engine fire is land immediately.
Land immediately (e.g. Engine FIRE -> land where you can)
Land as soon as possible and land at the nearest airport is the same (e.g. PFD fails but MFD and standby instrument is still working -> Pilot is able to continue flying but the safety margin is reduced)
Land as soon as practicable (e.g. Loss of vertical airspeed on the Standby instrument -> Pilot uses primary displays and vertical airspeed is not a critical parameter. This is a Minor failure condition which does not significantly reduce aircraft safety. Flight crew will decide if the failure does involve actions within their capabilities and if change in flight plan/mission is needed.


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Can you flag down / contact an airplane with a handheld radio in case of emergency?
A friend and I are going rim to rim to rim in the Grand Canyon this Wednesday.  It's a 46mi, 20+hr "hike" with some very physically challenging sections.  We are packing the minimal amount needed - meaning not too much extra in case of an emergency - it's especially risky given the below zero (fahrenheit) temperatures this time of year.  Normally for something like this, I would bring my Spot - to call for help if I needed to, but it's not working.
If I brought my VXA-220, would it be legal to use it to call for help?  From what I understand, most airliners are tuned into 121.5.  Could I tell them to send a helicopter for rescue?
Obviously, in a life or death situation it's not going to matter if I'm braking the law.  But it would be nice to know how such a situation would be handled.

Even if you get a good answer here, you may want to ask on http://outdoors.stackexchange.com as well, if you haven't already

I agree with @Pondlife that this question is more suitable for The Great Outdoors, because it more related to rescue than aviation. God forbid if you are in such situation, you won't mind if an ambulance is sent rather than a helicopter.

Since the SPoT neeeds to be replaced anyway, get a 406 MHz ELT.  It's the right thing for the job, it's airliner grade, and it works better in canyons (but not in mines or caves). Oh, the ELT will also warble on 121.5.   SPoT is a social media gadget wrongly marketed as an ELT.  Going on such a trip without some sort of ELT is nuts.

Great answer, Harper. The question is a little old though. Since this question is about hiking, a PLB like one from manufacturers ACR or by Ocean signal would work well. And, they are personal sized. I believe they are both 121.5 and 406 dual transmitting. The manufacturers include instructions and paperwork for registering them with SARSAT making them legal for emergency use.

Yes, this is legal. As far as I understand, it used to be common practice, and some hiker's beacons still squawk 121.5. Nowadays, more advanced beacons are suggested, but it sounds like yours isn't working. Some police and EMT stations still monitor 121.5, too.

Thanks for the info.  From what I understand (at least in the grand canyon), search and rescue is covered by tax dollars.  Would this be different calling via handheld radio as opposed to using a SPOT or similar?

I have no reason to think it'd be different.

For a bit more clarity, much like FAA rules, the FCC allows emergency deviation from any rule for amateur radio operators.  See 47 CFR 97.403 and 97.405. Perhaps one could argue this blanket exemption overrides the rules for a license at all. In any case, if it is truly life threatening and someone thinks it's illegal -- maybe they'll rescue and arrest you -- but point is you're still alive.

@dougk_ff7 I was taught that unlicensed operation was allowed in an emergency when studying for my amateur license; however, those two rules are restricted to amateur stations (so it doesn't seem like it'd apply to someone carrying non-amateur-band radios with no amateur license, only if there's already an amateur station present). For other services like CB, there's no corresponding rule (see 47 CFR 95.418); for ships, the call must be on the authority of a licensee (80.311); in general, it seems like the amateur rule is the exception rather than the norm.

That said, the FCC may well turn a blind eye to distress communications regardless of legality (particularly if you didn't plan to rely on that fact), necessity might be a partial defense, and an FCC fine beats death.

I downvote dangerously wrong advice.  Rather than DV this otherwise exemplary answer  for one  throwaway line about "maybe" getting billed for your own rescue, I edited to remove it. Authorities don't charge for rescues for good reason - they don't want people dying because they were afraid to call for help / called for help too late.  Making people even think to hesitate to call for help, could get them killed needlessly, hence the noxious danger of such advice.  If you feel otherwise, feel free to revert.

@Harper-ReinstateMonica Here's an article from Time claiming that in a number of circumstances, authorities do charge for rescues: http://content.time.com/time/nation/article/0,8599,1892621,00.html

@raptortech97 I saw that, but a) it's 2009 and b) "A friend and I are going rim to rim to rim in the Grand Canyon" NPS and USCG's philosophy is they don't want people dying for fear of the invoice.

The question is pretty old. This post is to add new info.
Since this question is about hiking, a PLB like one from manufacturers ACR or by Ocean signal would work well. And, they are personal sized. I believe they are both 121.5 and 406 dual transmitting. The manufacturers include instructions and paperwork for registering them with SARSAT making them legal for emergency use. You can also do this at:
https://beaconregistration.noaa.gov/RGDB/index .
Handheld airband transceivers are notoriously weak. Unless you have a perfect day, or you know how to construct the right antennae for your frequency and environment, you would be better off with a rented satellite phone than a transceiver.
If you already have the transceiver, and are determined to use it, a jungle antennae is your best bet. See here:
https://brushbeater.wordpress.com/2015/10/15/the-jungle-antenna/
A PLB is still the first choice.

Also, SPoT is not a 406 MHz ELT, they rely on private sat-phone networks and are not as reliable, especially not in canyons.  406 is scoped for the kinds of places airplanes actually go down.  Also the idea of an ELT being "broken" is insane; sounds like SPoT is a flimsy plastic e-toy, being mainly for social media, which means you can run down the battery in ordinary use and have none left for SOS.  A real 406 ELT has a long-lived one-shot battery. Break seal; await helicopter.  Also no monthly fees.

Bear in mind that the effective transmission range of many handheld airband radios is pretty poor - typically rather worse than the reception range.  And despite the NOTAM requesting aircraft to monitor 121.5 "when able", many do not.  So while it's better than nothing, it's probably not a good idea to rely on this means of calling for rescue.

This answer is for the United States only.
47 CFR § 87.43 states (in full):

§ 87.43 Operation during emergency.
A station [in other words, a radio set] may be used for emergency communications in a manner other than that specified in the station license or in the operating rules when normal communication facilities are disrupted. The Commission may order the discontinuance f any such emergency service.

I'm not 100% sure that this really does allow operation if you don't have a radio license at all, but it certainly seems to. (If you're not aboard an aircraft and the FCC hasn't given you a radio license, then you don't have a radio license at all.)
But it's only allowed "when normal communication facilities are disrupted." So presumably, if you have a cell phone or satellite phone you can use to call 911, you're required to do that instead.

I believe the reading "other than specified in the ... operating rules" covers cases where the user has no license as well as ones where the radio itself is out-of-spec. While getting my maritime license and my amateur license, I believe we were taught that in a real life-or-death situation, any person may use any frequency at any power to summon help. I would expect you to need to justify that you had no better means available and that your use was not needlessly disruptive. Caveat, I'm in Canada, not a lawyer, and (most importantly) not a federal prosecutor.


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What does aerodynamic noise of an airliner sound like in landing configuration?
I want to know what aerodynamic noise an airliner makes when flying with both engines shut down. Specifically, it is the sound made by air passing a plane which is in landing configuration, with gear and flaps extended, at a normal approach speed.
I know that it makes a loud noise especially during landing, but normally we cannot distinguish it from the engine sound.

No, you really don't

It's quiet, too quiet.

Follow by a very loud noise....

it makes a LOUD noise specially during landing

What exactly are you looking for? A description? A video? A sound file?

This question should be reopened.  The sound you're looking for can be heard here:  http://youtu.be/9ZBcapxGHjE?t=59s

This is a very good question, and I wonder why anyone would think it is unclear. It is not, please reopen it!

Although improved, I've voted to keep it closed, as it's still in a not-very-SE format. Where is the listener? How far away is the aircraft? What kind of aircraft? How fast is it travelling? Are we talking airspeed or ground speed? Is the RAT deployed? How about flaps? At what altitude? Is the landing gear up or down? Are the passengers inside screaming because the aircraft has no power and they're scared? This question does not have "an answer" it has "a range of conjecture and speculation which could give an idea of an answer with numerous caveats and ranges"

@JonStory: Come on, he says "especially during landing", and he is right; flaps and gear are major contributors. If you miss specifics, go ahead and edit them in - I'm fine with the question as it is.

Well I respectfully disagree. I certainly don't think it's unsalvageable, but it needs the addition of some context that the OP didn't provide. He mentions landings but doesn't state whether that's what he's asking about. If edited to be a more specific question, I'm all in favour of opening it again

I'm sorry, but I had to down-vote this. When I read the topic, my first reaction was "huh?" so I read the whole question, and afterwords, it's still that. I don't follow what the OP wants to know. Since more than one commenter thought it should be reopened, how about an answer?

Anyone got a video of maybe an emergency landing with both engine in-op? Or maybe statistic that such thing never happen so there is no example available online?

@vasin1987, they're extremely rare.  I've only found one airline flight (Air Transat 236) that performed an engine-out landing in the past 25 years, and another two (TACA 110 and the Gimli Glider) since the development of jet engines.

In fact, it's quite possible to distinguish the airframe noise from the engine noise when the airplane is close to landing.  Idling engines aren't THAT loud, and the sound they make when spooling up is distinctive.  Another interesting thing is that you can hear the wingtip vortices (or could before winglets) for up to a minute after the plane passes.  (Used to run just off the approach end of the local airport's main runway, so have heard a lot of them.)

One way to get an idea of what pure airframe noise can sound like is to visit an airfield where gliders are landing at the end of a competition.  Streamlined fiberglass gliders will come into the field very fast and low, with no engines, making astounding noises.  They're not airliners to be sure, but they are not as silent as you might imagine, and the noise they make seems similar in some ways to that of a jet aircraft.

Aerodynamic noise has many sources. It is not white noise, because some frequencies are dominant. Generally it happens when flows of different speed collide, or when a standing wave develops in a cavity. Common noise sources are:

Uncovered openings, like vent holes or control surface gaps. Like when you blow across the top of an open bottle, they produce a howling sound with a dominant frequency that depends on flow speed and opening size.
Tollmien-Schlichting waves in the boundary layer. These frequencies change with speed and their location along the flow path, and generally are responsible for most of the hissing sound of gliders.
Separated flow, which produces alternating separations behind blunt bodies. Here the main frequency is that of the Karman vortex street that forms behind them. It can be calculated if the Strouhal number Sr of the flow is known. This is the equation for the main frequency $f$ of a bracing wire with the diameter $d$: $$f = Sr \cdot \frac{v}{d}$$
Here $v$ is the airspeed, and for bracing wires Sr is normally 0.2. Bracing wires (or a blunt trailing edge, for that purpose) produce a characteristic whistling sound.

As you said, the landing configuration makes most noise. In addition to the factors above, you now have

Extended flaps, mostly with gaps between them which show high local flow speed. This local high-speed flow is very noisy.
Many more blunt objects sticking out of the airframe: Landing gears, gear covers or landing lights. The particular noise of landing gears was once tested with a high-performance glider which had styrofoam gears fitted under the wings. They broke off when it had to land, but yielded valuable data when compared to the noise of the clean glider. Sorry, there is no photo of this experiment on the web!
The gaping hole of the landing gear well. Especially while the gear is moved, this creates a lot of noise, but even after extension a part of the well is uncovered and adds its noise.

Here is a good overview of different noise sources. It is best read with a good working knowledge of German.
To answer your question: The sound is a mixture of hissing and whistling in different frequencies. If you stand close to the Autobahn (best is a section without speed restrictions), the noise of the passing cars is similar, but less intense. At 180 km/h, engine noise starts to vanish in all the aerodynamic and tire noises ...

Thank you Peter for the details. I was looking for a video or a sound sample

@waelrokbani: I found the question interesting and worthy of an answer. However, I wouldn't expect that this video has yet been made. The best you can get is a video with engines idle, but still running - that reveals already much of the aerodynamic noise.


text:
Why do helicopters and airplanes use different headset plugs?
If the headsets and microphones for general aviation have the same impedance for helicopters and airplanes, then why do they have different connectors on them?
Is it simply to make more money from selling adapters and more headsets?

It's a holdover from the old days when microphone technology wasn't as advanced.  The military adopted "dynamic microphones" as the standard, which were less noisy than the alternative "carbon microphones."  Carbon microphones required a DC bias voltage to operate, and the dynamic ones did not.
Fast forward to current airplane microphones, which are electric, and still use a bias voltage, so if you plug a military dynamic microphone into a civilian airplane jack, the microphone would burn out from the voltage.
So what?  Well, helicopters were originally very military oriented, so they all were wired for dynamic microphones.  They used a different jack to avoid accidentally plugging the wrong type of microphone into the wrong type of jack.  Even though helicopters are widely used outside of the military now, the standard remains, and many emergency radio equipment (fire, medical, police, etc) still uses the dynamic standard.

Just as an FYI, the military (or helicopter) plug is referred to as a U174. Often times both the U174 and the Bose LIMO jacks are both installed in helicopters.


text:
Why do most single propellers have a clockwise rotation?
Why do most single propellers have a clockwise rotation (seen from the pilot's point of view)?

There are though multi-engine planes that have each propeller rotating different directions, but in the case of single propellers, it seems that clockwise rotation is dominant, or even the only option. Is there any single propeller plane with counterclockwise rotation?

It is a cultural thing.

Or maybe because some engineer wanted the angular momentum vector pointing away from the airplane in his drawing.

I assume it has to do with the way the engines are made.  There are only 2 major companies that make small plane engines.  No doubt people with design skills have moved between them and done things that same way in both jobs.

And, for a serious comment.  The Piper Seminole (twin engine) has each engine spinning in a different direction to help counteract left turning tenancies.

To answer the last part of your question, yes, there are single propeller planes with counterclockwise rotation: Zlin 26 series and the older versions of the Zlin 42 series.

@KeeganMcCarthy Are there any twin engined planes that don't have their engines spinning in different directions?

@SQB, yes.  I believe most transport twins have identical engines/props for ease of maintenance.  Example: https://www.flickr.com/photos/thomasbecker/4714404607/

@BowlOfRed is correct.

I don't think this is relevant, but just in case: is there a difference when it comes to hand-starting? (of course, if there is an advantage to a right-handed person, it is probably a disadvantage to a left-hander.)

South of the equator they rotate counter-clockwise ;)

Aft engines (props behind the cabin) rotate the opposite direction when viewed from the front.

Cessna 337 (Military O-2A) had same engine in front and in back, both props rotated the same relative to engine, but this meant they rotated opposite to one another relative the airframe.

Correction: Most Western single engine planes have clockwise rotation while most Russian (especially Soviet) single engine planes have counter-clockwise rotation

I wasn't able to find any good historical references, so this answer is pure opinion.  (sorry).  I'll break this down into two separate questions.

Is there any reason for single-engine propellers to turn the same way?

Yes.  When flying, the spin direction of the prop has several effects.  Helical prop wash, p-factor, gyroscopic precession, differing blade angles of attack all are due to the asymmetry of spinning in a single direction.  An experienced pilot will want to understand and compensate for these effects when necessary.  It is easy to see that once this is understood, a single configuration will be preferred within a community to minimize differences between aircraft.

Is there any reason to prefer CW rotation over CCW as a convention in a single engine plane?

None that I am aware of.  It appears to be simply an accident of choice.  I had wondered if the majority of engines available to early manufacturers was in that direction and made it preferable, but I couldn't find anything suggesting that.  Indeed today the majority of automobile engines rotate the opposite direction.  Making (piston) engines rotate the other direction is not a huge problem.  Twin-engined aircraft and watercraft often have counterrotating engines and propellers.

Note that helicopters with a single main rotor built in the USA rotate clockwise (looking up), but those built by Airbus/Eurocopter turn counter-clockwise. Pilots of US-built plane use the right pedal when adding power, and the Eurocopter pilots press the left pedal.

This seems to be the only answer that gets at the critical issue - (single-engine) pilots have an ingrained habit of pressing the right rudder pedal when climbing/accelerating that depends on rotation of prop direction. I would find it very difficult to fly with this reversed, myself. And the vast majority of twins have props that rotate the same way, FWIW. I can only think of a handful (Pipers) that have counter-rotating props as the advantage is small and the cost is high.

I don't try to remember which pedal to use, I step on the ball (airplane) or the based of the yaw string (heli) to fly in trim.

The reason I had heard (again, no citation available) was that by having this setup, the plane would be more likely to bank left due to the propellor, and with the pilot sat on the left of the cockpit, they would then have a good view to be able to remedy it.

Indeed today the majority of automobile engines rotate the opposite direction.

Not quite. The power output of a car engine is towards the rear. The power output of an aircraft engine is toward the front. If you look straight at the flywheel / propeller end they usually turn the same way.
Back in WWI the first-generation fighters (We're talking Sopwith Camels and Fokker triplanes here) did have props going in either direction. The airframe manufacturer made the whole thing and props were carved by hand, so it didn't matter much.
Today we have a small handful of prop makers, a smaller handful of engine makers, and both of them would be quite happy if everything turned the same way. Yes, it's really easy to make a piston engine go the other way, and it's really easy to flip the prop's airfoil over, but that means making and stocking different parts. The camshaft, pumps, ignition timing, prop governor, starter, mechanical meters etc. are all directional. And don't forget the pilots - if he's used to putting left boot to it on takeoff, and rents one that needs right boot, takeoff will be interesting.
If your twin or multi has counter-rotating props you have some advantages if one quits but you have extra maintenance costs. Imagine the language your mechanic will use after changing the camshaft and then remembering this engine is a leftie when he tries to start it.
If it's a geared engine then it's much easier - the engine and accessories are standard, there's just an extra (or one fewer) bit in the gearbox, plus the other-hand prop.

Are there any aircraft with counter-rotating engines? I believe counter-rotating propellers usually have the same engines behind them and just different gearboxes.

Yes, a bunch us counter rotating engines.  For example the Piper Seminole: https://en.wikipedia.org/wiki/Piper_PA-44_Seminole

It's really easy to design a prop or engine to turn the other way, but a lot less easy to make an existing one go the other way.  You have to disassemble the engine and change the camshaft (and more), and put new blades on the propeller.

"And don't forget the pilots - if he's used to putting left boot to it on takeoff, and rents one that needs right boot, takeoff will be interesting." Wouldn't the pilot likely notice that already during the taxi, seeing that he needs to use a little more right boot?

@pericynthion  Some Perkins diesels (used in naval boats) could run in either direction. The camshaft drive is a gear sequence. You set the engine to TDC, and  there is a lever that shifts one gear out and two smaller gears in. That reverses the relative direction of the crankshaft and camshaft. You restart the crankshaft in the reverse direction. All the valve gear, fuel punp, oil pump etc run off the camshaft as before. The crankshaft and pistons don't care which way round they go, and the propeller turns backwards.

I am quite amazed no-one has hit upon the obvious, its all to do with starting. Being both a pilot and totally arrogant of the unfortunate minority who are left handed. On a car with a starting handle, I would cup the handle in my right hand and with a mighty swing. Spin the handle from a low point 'upwards' and physically towards my center of gravity causing the engine to turn in a clockwise direction as viewed from the front.
Starting handles; what are they? Great lumps of bent iron which could be fed through a hole in the bumper and engage with a dog on the end of the crankshaft.(quite sure these keys and starter buttons will never catch on) And here is the reason; a petulant engine on a damp cold day will do anything to stay in the garage, include oiling its plugs and electrocute anyone's hand that is fiddling with the HT leads, and after half a dozen attempts at starting, the battery will go flat, hence out will come the handle.
In a politically correct world the majority would bow to the misfortunes of the minority but after swinging an engine for half an hour 'sod the left handed minority'.
So there you have it, its a throwback to the golden age of motoring and right handed people rule but what about aeroplanes.
There is no simple way of saying this but; stand in front of a PA28 with a 140 horse power engine with a metal prop and a flat battery, (probably the finest mincing machine known to mankind).
Facing the aircraft with mags and switches off, the propeller would be turned by hand to a point where the compression on the engine is just building then stand back. A command to make the engine live is given.
If the rotation of the engine is counterclockwise as viewed from the front of the aeroplane, a stance is made forward and clear of the arc of the propeller. Just the fingertips of the right hand grasp the trailing edge of the blade and in a single pull; spin the propeller over top dead center and instantly clear the arc of the propeller. This is a highly dangerous practice but can safely be accomplished with care.
If the rotation of the propeller were to be to the right or clockwise as viewed from the front, I would then grasp the propeller with the finger tips on my left hand. (as I am right handed) I would hold hands with another person standing behind me to prevent any possibility in over balancing.
----------There is absolutely no reason why an engine or propeller should have a preference to turn in either direction apart from commercial considerations, custom and practice and the desire for safety in hand starting the contraptions-------For the record I ran an airflow test laboratory for many years and I can assure anyone that the absorbed power of a fan, provided it is of a mirror airfoil section will be identical.

...when did you get your car with the starting handle?

@Sean Not that rare... Starting handles were standard equipment in all Renault cars made before 1967. They were very practical when batteries went flat...

Fascinating answer; it would be interesting if any one could find any proof that ease of hand-propping was actually taken into account by engine manufacturers when choosing the direction of rotation.

This has the ring of truth, and I want to believe it.

I'm in the USA, and I have crank-started a 1966 Datsun (before they changed to Nissan) pickup truck.  Fortunately, it was only 1.3L engine, so it wasn't a great trial; also fortunately, the engine was freshly rebuilt and had good compression, new plugs, points, wires, and distributor cap, and the carburetor was in good adjustment.  There was no fixed crank, like a 1920 Ford; rather, the jack handle served.

I suspect ease of pulling over the starting crank is not the true reason. The boss that the crank mates into would screw onto the front of the crankshaft with a right-hand thread. Cranking the engine anti-clockwise would unscrew that boss, not start the engine. Worth mentioning the boss has angled slots to eject the crank when the engine fires up: I once used a rusty crank that stuck in and flailed around at 20 revs a second while I nursed my knuckles.

The question for different prop rotation is very much like driving on the right side of the road (in North America), vs. on the left side (in the UK, Hong Kong, India, Japan etc.) It's all wrapped up in history and perhaps politics. BTW, Rolls-Royce turbofans turn CCW, but most GE and P&W fans turn CW. There's no performance advantage, one way or the other.

One other thing to note. Standard airport traffic patterns have the airplane turn left. We're taught that this is because early airplanes like the Sopwith Camel had clockwise rotating rotary engines and propellers. The engine and propeller are a gyroscope and have a great gyroscopic effect on a light airplane like the Sopwith Camel. Gyroscopic procession for a clockwise rotating engine and propeller meant that right tuns tended to force the airplane down into the ground (bad) but left turns tended to force the airplane up (good as long as you don't stall). Also, pilots sit in the left seat, so they can see where they're going in a left turn.

They don't! In s̶o̶v̶i̶e̶t̶ Russia, they rotate counterclockwise. Additionally, on some multiengine aircraft, they rotate opposite directions to cancel the p-factor.

[citation needed]. For example, Wikipedia claims that generally turn clockwise as seen from the rear of the aircraft, making no mention of exceptions except for contrarotating props.  (Admittedly, Wikipedia needs a citation, too.)

The Su-29/Su-31 planes are examples of Russian planes with counterclockwise props. A non-Russian example that comes to mind is the Griffin-engined Mk. XIV Spitfire. The P-38 Lightning and Beechcraft Duchess are examples of twin engined planes with counter-rotating props.

IIRC, My flight instructor (who is Russian) said that they usually spin counterclockwise in Russia. It's been a while, though, so I could be remembering incorrectly.

@DavidRicherby: Look at images of Russian planes such as the MiG-3 and the Il-2 on Wikipedia and you'll see that the props turn counter-clockwise. In fact, some articles even mention this but not all. But if you do look at all examples of Russian planes you'll find that almost all (or actually all) their props turn counter-clockwise. It is on Wikipedia - you just need to look closer.

The only case where I would consider an advantage or disadvantage may be observed in selective airflow is in that single engine German observation aircraft of WW2, the Blom & Voss 141 where the single engine is located to the starboard of the fuselage. Albeit the propeller is located forward of the main body, but the prop wash may have a disproportionate effect, depending on its direction of rotation when acting on the aircraft non symmetric profile.
I have designed a multitude of rotating and velocity activated systems, including the testing of a ballistic polymeric material at, of all places 'The Balloon and Cordage  Department' at the RAE Farnborough, also piloting aircraft with CW & CWW rotating engines and nowhere in free field applications, will the direction in rotation of the propeller or the engine have any preferential effect whatsoever.
Dare I suggest a brave response may visit cyclic forces in the Northern/Southern Hemispheres!

I remove some parts of your answer because they seemed totally irrelevant for the question. I'm not sure if you even intended to add another answer. You can edit your previous answer by clicking on the edit link below it, if that's what you wanted. Also, please have a look at the tour to see how the site works.


text:
What is the weight at which an aircraft no longer requires a licensed pilot on board in Europe?
According to this (somewhat dubious looking article):

Since it is so light, the FlyNano falls under the weight of what is considered to be a plane, so in most countries you won't need a flying license to take this baby to the skies.

The aircraft weight needs to be 70 kg or less. FlyNano mentioned this on their FAQs page (my paraphrasing):

Do I need a pilot's license to operate FlyNano?
According to the European Aviation Safety Association regulation
  ... FlyNano is below the necessary weight of 70kg ... In Finland for
  example no classification, no aviation license or medical
  certification are needed. But skill is needed. Nevertheless a good
  understanding of water plane operation, rules and aviation safety is
  requested. ...

I found that any aircraft less than 70kg is not affected by EASA regulations. But regardless, and emphasized by FlyNano also, pilot skills are required.

This also says that Amateur/Experimental built aircraft are exempt regardless of weight.

I found this document that seems to have the full legal code that lists these points. http://eur-lex.europa.eu/legal-content/EN/ALL/;ELX_SESSIONID=CDMWJhrZLxpHyJ3QRN4v18gvYJpZ1pnGWZdGj91SYZYdsGvvrcGx!1674962396?uri=CELEX:32008R0216

@LewisGoddard Sweet, gonna build me a Concorde!

One important thing to note from that FAQ, though is "FlyNano is below the necessary weight of 70kg, which means that national authorities decide on the classification." So, no license is required in Finland, but the requirements might not be uniform across the E.U.

@reirab As I posted further up, these are actually European legislations that exclude it from their licensing. Countries could add their own, but by default, you're all good!

@LewisGoddard Right, that was my point: while EASA does not regulate such aircraft, individual countries may have their own rules for them, so someone wanting to fly one should still check with their local regulations.


text:
Can a student pilot start flight training before they get their student pilot certificate and medical?
Let's say someone wants to start doing some flight training in the United States with the eventual goal of receiving a private pilot certificate. They have yet to get a medical certificate or student pilot certificate. Can they go ahead and start getting some flight training logging dual received?

Yes.
14 CFR 61.87(n)

(n) Limitations on student pilots operating an aircraft in solo flight. A student pilot may not operate an aircraft in solo flight unless that student pilot has received:

(1) An endorsement from an authorized instructor on his or her student pilot certificate for the specific make and model aircraft to be flown; and
(2) An endorsement in the student's logbook for the specific make and model aircraft to be flown by an authorized instructor, who gave the training within the 90 days preceding the date of the flight.

14 CFR 61.23(a)(3)

(a) Operations requiring a medical certificate. Except as provided in paragraphs (b) and (c) of this section, a person— ...

(3) Must hold at least a third-class medical certificate—

(i) When exercising the privileges of a private pilot certificate;
(ii) When exercising the privileges of a recreational pilot certificate;
(iii) When exercising the privileges of a student pilot certificate;

The student pilot only needs a student pilot certificate and medical when operating in solo flight.
With that said, if there is any doubt that a medical certificate won't be granted it is a good idea to get that out of the way before spending money on flight training you will never be able to use.

The FAA regulations allow for individuals to receive flight instruction from a certified flight instructor (CFI) without holding a medical certificate or student pilot certificate. However, before they can solo or act as pilot-in-command (PIC) of an aircraft, they will need to obtain a medical certificate and a student pilot certificate.


text:
Can light GA aircraft implement fly-by-wire technology?
Theoretically, I know it is possible. I know the benefits of fly-by-wire too.
My question(s) most revolve around:

why it hasn't been done?
What challenges1 would there be?
What benefits are there by not implementing it even for new light GA aircraft2 being produced?
I know that many smaller airplanes (e.g. Cessna 172) do have fly-by-wire flaps. Why the remaining flight controls don't use this technology?

1: Not considering money as an issue.
2: I couldn't find any reference of it for Cessna Skyhawk.

I know that FCS (Flight Control System) is really expensive to develop, so only affordable for big production rates... so if money is not an issue I don't see any limitation, but I can not tell you for sure this statement

DA-42 converted to fly-by-wire: http://www.flightglobal.com/news/articles/diamond-tests-fly-by-wire-on-da42-380035/ [en], http://www.ils.uni-stuttgart.de/forschung/projekte/safar/index.html [ger/en, technical], http://www.avweb.com/avwebflash/news/da42_flybywire_diamond_autonomous_control_pilot_207775-1.html [en],

I do not consider the 172 flaps to be fly-by-wire.  To me, FBW means the PIC provides input, which a computer interprets, modifies, and limits before acting on.   The 172 has electrically controlled flaps.  When I move the lever to flaps-10, the motor moves the flaps, but with zero authority to do anything other than what I commanded.

"What challenges would there be, not considering cost as an issue" ends up being pretty close to a null-set of issues. Most challenges in engineering & design end up being matters of cost. "We could do that, but it will cost..." is generally the reason that all sorts of otherwise cool ideas aren't implemented. With hundreds of engineers, full scale test facilities, and unlimited prototypes, not much remains as a challenge.  As you say, it's clearly possible, and between things like the A-320, the B-2, and the F-16, the theoretical issues are solved, so the remaining challenges amount to $$.

@abelenky FBW only means that surfaces are controlled "by wire" as opposed to by mechanical/hydraulic linkage. I believe the first FBW Airbus aircraft had no interpretation or limitation in the line

@raptortech97: Citation needed, or its just an opinion.  Personally, I see no difference between a direct mechanical linkage, direct hydraulic linkage, and direct electric motor linkage.  FBW means there is a is a computer interpreting commands, and inputs are not direct from PIC to control surface.  Wikipedia agrees with me.

You asked what benefits are there by NOT implementing it, but neglected to ask the obvious corollary question.

@MichaelHall - Good point. Unless it can be proven to have a safety benefit, a cost savings to manufacture, a cost savings to maintain, an increase in fuel efficiency, or some other reason to make a consumer desire it, there would be no reason for the manufacturer to go through the trouble. Only legislative reasons would make them do so. The biggest downside would be for the non-commercial pilot. Some enjoy flying for the sake of flying. Just like some people drive manual transmissions for the fun, connectedness, and purity of it.

I'm no expert, but I'd guess that fuel injection will be common in general aviation long before fly-by-wire.

There are multiple factors here:
The first and main one is of course weight. Fly-By-Wire requires computers and hydraulics to actuate the surfaces in a small plane weight is critical and a FBW system may be the difference between 3 and 4 passengers in total capacity.
The next that comes to mind is certification, I'm not sure exactly how this works but I would think that FBW implementation in a current airframe would require a recertification of sorts. With that being said many GA planes flying out there like the 182, Piper Arrow and other similar things still made today are sporting designs first flown more than 30 years ago. It's a simple matter of, "if it ain't broke don't fix it".
I would think that basic service and maintenance would also become more complex and worst of all more costly. I don't know much about the cost of these systems so I wont comment father than speculation like this.
There is a safety concern in small planes (and I'm sure even bigger planes) if control feedback is not present. This Article outlines some serious concerns with the Cirrus side stick and its lack of feedback (not fly by wire but some of the ideas carry over to the FBW systems that don't have feedback).
A Note on the 172:
The way I understand FBW leads me to think the 172 does NOT have FBW flaps. While they are electronically actuated I consider FBW (and by definition):

...flight control computers determine how to move the actuators at each control surface to provide the ordered response

There is no computation done in a 172's flaps to my knowledge, if you move the switch they will move. While the flaps are not directly cable driven I would consider the lack of computer to keep the 172 out of the FBW category but thats just personal opinion.
Also of note, the 172 did not always have electronic flaps - that was a later addition to the aircraft in '65.
A Note On Cost:
Although you note that one must ignore cost in this case you really can't. A FBW system would make a GA plane even more expensive than they are. This is a very real and very limiting factor in aviation. With an unlimited budget you could develop, certify, and regularly fly a FBW small plane that was chock full of gadgets but the FAA approval process is what it is and cost is a very real limit for aircraft makers.

+1, especially for the last paragraph. We'd do a lot of things different in GA if cost weren't an issue. For instance, there would be a lot more people flying jets around and hours would be much easier to come by. :) I don't know about you, but, if cost weren't an issue, I'd be learning to fly a 777.

Re the 172's electrical flaps, I found I much preferred the manual flaps on my Cherokee.  I think that would go across the board: unless there was a MAJOR performance/efficiency advantage to be had from FBW, I wouldn't want it, any more than I'd want a car with automatic transmission.

@reirab: Yeah, and let's see you land that 777 on an Idaho backcountry strip :-)

The biggest reason that fly-by-wire hasn't been implemented yet is the complexity of the change required. Larger aircraft already started using hydraulics to move their control surfaces, and a fly-by-wire system adds to this by actuating them with a computer. Smaller aircraft do not have the need for hydraulics, so they must move from direct linkages to computer control. As ratchet freak says, this adds a lot of weight and complexity.
Flaps are much more simple than a whole control system. They don't move very often, and if they fail, the plane is still able to take off and land safely. The pilot directly controls them on a simple scale of up to down. The rest of the flight controls must be able to move throughout the flight, be quick to respond, and implement computer control logic. Failure is much more critical than the flaps as well.
There is also a large inertia of history to overcome. The industry is used to traditional control linkages. Moving away from this will incur a large cost in developing the system, testing it, and getting it approved by regulators. With sales at their current levels, adding this to older designs may not be worth the cost of development, and new designs would have to make the option attractive compared to other options.
A big hurdle to overcome is also safety. While larger aircraft have managed to implement these systems, the challenges are greater with smaller aircraft. Mechanical controls are generally more simple to inspect and repair, and the GA maintenance community would have to learn many new skills to work with the new systems. Redundancy and safe back-up controls would have to be included in a smaller airframe. All of this when regular controls work perfectly fine and are efficient in cost, weight, and complexity.
As reirab commented, stall training is required for a PPL. It makes sense that pilots should still know how to handle a stall, in case the protections fail. But this means the system must have an option to be inhibited. So although the plane should usually prevent stall, pilots will also need to know how to recognize and handle system failures, which even experienced pilots with an ATPL can struggle with.
So what benefits are there? Safety is one area where fly-by-wire can offer great improvements. A fly-by-wire system can automatically prevent the pilot from stalling the plane or otherwise putting the plane in a position where it is out of control. These kinds of incidents are much more common in general aviation than with airliners, so there is a huge potential for reducing the number of accidents. The plane can also trim itself automatically and deal with many of the aerodynamic idiosyncrasies that different small planes have.
There is progress being made here though. Fly-by-wire technology has been used on business jets like the Dassault Falcon 7X. Diamond is working on a fly-by-wire option for the DA-42, as well as the future DA-62. As of 2012 they were hoping to have this available around now, but there are at least manufacturers working on bringing this technology to market.

One note on envelope protection: It's often not desired in GA. While you certainly don't want your pilot to stall an airliner in which you're riding, it's actually very common for GA pilots to intentionally stall the aircraft. At least in the U.S., demonstrating stalls and recovery is required in order to get even a private pilot certificate. At the very least, the pilot would have to be able to manually disable envelope protection if it were implemented in a GA aircraft.

@reirab Good point, and that has its own issues.

Fly by wire costs weight in actuators for the control surfaces and power to move those actuators. It's simpler if there are hydraulics already needed but many small GA use pulleys and control-rods to link the control surfaces to the controls.
Then you need a few computers (redundancy) and sensors feeding into them.
Also the plane should still be safe to fly and be able to make a controlled landing after the fly-by-wire system fails entirely.

COST like most things that could be added to light aircraft and are not because it is not cost effective to do so.  Especially given that most light aircraft are based on 50-60 year old designs.   The Cessna 172 entered service in the late 1950's.   They would have to do a complete redesign of the aircraft which would cost millions to develop and certify.  The finished aircraft would be very expensive and people may not be willing to pay 700,000+ for a standard performance 4 seat light aircraft.

A bit of history helps here.  As planes got larger, manually activating control surfaces became more and more difficult, so mechanical assists, such as hydraulics came into use.
As in operating a hydraulic shovel or a hydraulic lift, the inputs are still controlled by moving a lever or turning a knob by hand. Indeed, even a remote control radio signal turning an electric servo is still a mechanical extension of a physical command by the pilot.
"Fly by wire" implies a physical input, changed to an electrical signal, transmitted to a control surface servo, which moves the control surface.  Electrical flaps could be considered fly by wire with that definition.
But the modern "Wikipedia" definition also implies that a computer determines the amount of movement the control surface makes, putting us two steps away from knowing if and how much a control surface will actually respond.
For very large aircraft, mechanical boost is needed (imagine trying to open a barn door in a hurricane).  For borderline stable aircraft, like modern fighter planes, computer "artificial stability" must be added to make the plane flyable.
Neither are needed for a small, soundly designed GA plane like the 172, being flown in VFR conditions.  However, applications for higher technology do exist for collision and terrain avoidance and flying in less than ideal conditions.  This would represent a step up from purely recreational flying, which is generally done in fair weather.  An autopilot can certainly be a life saver.
But with a smaller aircraft sensor inputs go to the pilots brain and controls are moved with hands and feet.  Mechanical and computer systems, which are expensive, complex, and require sufficient redundancy to be safe, are not needed.

Let's not forget the liability issue.  Practically every GA accident that results in injury or fatality results with a lawsuit. That's one of the biggest reasons we have such old technology for which we pay such high costs.

It is actually technically possible to implement FBW in light aircraft. Technologies like Horizon Hobby ASX, SAFE & A3D already provides a FBW for RC planes, drones and helicopters. Likewise, the drones like DJI do have "follow me" mode where the drone is able to follow a person on bike or on foot at a set altitude and attitude. So, technically, it is possible. It's already implemented there. Just need to find some GA aircraft producer to bite the bullet and get these stuff and certificate and integrate in their products.
By the way, with FBW, you generally use electric servo motors, not hydraulics for control surfaces.

I'm not clear what this adds to what the OP already acknowledged... theoretically possible, etc.  The question has some rather specific inquiries, and "drones do this already" doesn't address those.

"you generally use electric servo motors": maybe in drones. FBW aircraft like A320 or B777 use hydraulic actuators. At this size, electric servo motors are no longer feasible.

F16 uses electric motors and fiber optic control lines. The OP asked about general aviation planes, where hydraulics would be totally unfeasible but electric servos would perfectly provide a control force comparable to a human. Thus, in my opinion, it is only a matter of time for a GA producer to come up with FBW to improve handling and safety.


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Do aircraft have siren to warn public in case of a crash over land?
The recent crash of a Taiwan aircraft, got me thinking, do aircraft have built in siren, which can warn people on the ground of a possible crash to give them some headway.
If that is not practicable or feasible, then what solutions are feasible, or one should abandon the idea altogether and think of making planes safer in the first place?

If the aircraft is about to crash, you should expect failures of several systems, including the siren (not usefull to control the airplane, e.i. not as redundant as other critical systems). Moreover, with all the potential alarms triggered in the cockpit of an airplane, the siren's noise could disturb the pilot.

Planes are already safe. Such siren would be useful on really rare occasions (maybe less than once per year), so unless someone find a cheap solution that introduce no complexity, the cost to develop, certify and install such a solution would be dissuasive

You should look into the Jericho-Trumpet! The Germans did this; It was a powerful psychological weapon. https://www.youtube.com/watch?v=nZZ504TGDpE

I understand where you are at with this, I'm going to start off with a bit of math to show how it's not workable. Commercial airliners move quickly, even in a controlled glide one is going close to 3 miles (4-5 km) per minute. To give people on the ground enough useful warning to perhaps find some sort of cover you would need to give at least 20 seconds. This siren would have to be able to penetrate the walls of buildings and houses and cut through the background noise of a built up area at least a mile ahead. This is a very powerful siren and you'll have the following challenges:

At close range you would deafen anyone nearby, injuring the people you are trying to warn
The mechanism to generate this siren would likely be large, heavy, and challenging to design into an aircraft frame
You would need a great deal of mechanical or electrical power to generate that amount of noise. If you have no engine power you won't be able to sound the siren, and if your engines are working you won't need to as the engines make very good sirens already

There are very, very few cases where a siren such as this would save very few lives compared to justify the costs.

While it's true enough that aircraft engines are extremely loud, just hearing an aircraft engine doesn't by itself alert you to the fact that something is wrong. I'd even go so far as to say not hearing the engines when an aircraft is nearby is a better indicator that something is wrong. :)

+1 for discussion of how loud the siren would have to be, though. In addition to the people on the ground, it would also render the pilots unable to communicate with each other or ATC and quite likely incapacitate them entirely, which will almost certainly lead to a worse outcome than in the absence of the siren. Also, the audible range of the siren in the area that the aircraft is moving towards would be greatly reduced from normal because the aircraft is traveling at a very significant percentage of the speed of sound.

It's true that hearing an engine doesn't by itself mean something is wrong, however hearing one out of place certainly gets your attention. People are generally attuned to their environment, hearing a jet close by when you're not near an airport would be noticed.

To put some concrete numbers on the loudness: if you want to produce 90 dBa at 2000 meters (ie. what you'd need to be heard over the noise of a busy road), the siren would need to produce 156 dBa at 1 meter (ie. louder than a jet engine), and the 130 dBa threshold of pain would be at around 20 meters (ie. a 737's cockpit would be inside the pain zone of a center-mounted siren).

I didn't know that people inside the plane are not insulated from the loud engine noise of a jet, as some are suggesting. Am sure if there is insulation from loud sound, then a siren won't interfere would the passengers or the pilots.

@Mark An open 737 cockpit would be inside the pain zone. But 737s don't have open cockpits and are quite well insulated from the sound. For example, pilots and passengers aren't deafened by the engines.

@Mark, Actually, it would require even more than that to reach 90 dBA 2 km ahead of the aircraft (which is presumably the place you'd want to alert.) This is because in the time it takes the sound to travel those 2 km, the aircraft itself has traveled a significant percentage of that distance, which means the distance from aircraft to person will be significantly less than the original 2 km when the audible level actually reaches 90 dBA at the person's location. Another thing to note here is that this isn't much of a warning. That's probably around 20 seconds of warning for an airliner.

I like the speed and warning points being made here, but I think the sound volume is something of a red herring. Even if everyone in a 1-mile radius could be made easily and instantaneously aware of the fact that there is a plane in distress in such-and-such direction, the fact is that when the plane is still 1 mile away it's impossible to judge its trajectory well enough to know which way to run (or whether to run at all). Once the plane is close enough that you can know it's going to crash near you, will be too late to run anyway.

Running away would make no sense, the only real option would be to try and find some cover or protection. 20 seconds may be enough time for a few people to put a brick wall between themselves and the airplane or go into a basement. It's pretty marginal though.

What about GA aircraft, which fly more slowly and crash more often?

No they don't.
If you think about it, it is very rare for an aircraft to crash into a built-up area. People on the ground would have very little time to hear a siren from an aircraft approaching at a hundred miles per hour or more. Anyone hearing it might be as likely to run into the path of the aircraft rather than run away from it.

Of course, it's rare for aircraft to crash at all. But, if an aircraft does crash, it's quite likely to be soon after take-off. Since many airports are in or close-to built-up areas, such crashes are often in built-up areas. Examples include TransAsia 235 (as mentioned in the question), Air France 4590 (the Concorde crash) and El Al 1862.

Arguably US Airways 1549, too ("The Miracle on the Hudson"). Also, TransAsia 222 crashed into a built-up area on approach.

No they don't, crashes over land where the plane was stable enough to provide enough warning to the people on the ground are very rare.
The only incident that would have benefited from it which comes to mind is the gimli glider.

except that landed safely.

and nearly killed 2 kids riding their bike on the (decommissioned) runway

@ratchetfreak: Never mind two kids riding their bike - how about the dozen stock cars and associated spectators holding a drag race.

No, and even if they did you would probably not hear it. Engine noise should be enough to alert someone who is paying attention, but the truth is that the average pedestrian has no cognizance of unusual noises.
Also, the odds of hitting a pedestrian are extremely remote. Most people move around in cars. Unless you are landing on a park or a beach there will generally be noone around.
I did hear of one case a couple of years ago where a guy ran out of fuel and landed on a beach and killed a jogger. The jogger didn't hear him because he was wearing headphones.
When you come down it all happens really fast. A pedestrian, even with a lot of warning would have to be paying attention, be alert and react right away. Most people are absorbed in what they are doing and a siren going off 1000 feet away and 300 feet up is not going to be on their radar.

I'm not sure why you assume that the only people on the ground who might need to be warned are pedestrians. Also, a plane that has run out of fuel is a glider, and gliders are very quiet.

@DavidRicherby Well, if they are in a car, they are definitely not going to hear anything (unless its a convertible LOL). Also, in a car there will be lots of noise from your car plus the cars around plus the radio plus the book you are listening to plus the guy you are talking to on the cell phone, etc. Something thousands of feet away will be completely invisible. When planes land on highways, it is always a complete and total surprise to the motorists to whom the plane "appears out of nowhere".

The fact that fire trucks, ambulances and police cars carry sirens to alert other road users clearly demonstrates that motorists can hear sirens outside their vehicles. In fact, forget the emergency services: every motor vehicle is equipped with a horn. Audibility to motorists is not the reason that planes don't carry sirens.

@DavidRicherby I know that, I am just saying the utility of a siren, even in an emergency situation, may be a lot less than the OP imagines. There is a big difference between a fire truck coming up behind you and a plane landing on you. Most people don't make any changes to their vehicle's heading until they can SEE the threat vehicle.

@DavidRicherby Excellent explanation there, maybe you can draft an answer on should airplanes have sirens

@Firee Thanks. I've not written an answer as I don't think I have anything to say that isn't covered in the existing answers.

@DavidRicherby a plane that has run out of fuel is unlikely to be able to power a siren

@DavidRicherby An airliner makes for a really big glider. The engines are not actually that much louder than everything else.

@MattNordhoff I was addressing Tyler's remarks about what was, as I recall, a light aircraft making an unpowered landing on a beach.

Sadly, I've noted that sometimes, people are completely oblivious to lights and sires of emergency vehicles. I've seen people drive 1/2 a mile or more with an emergency vehicle behind them - lights flashing, siren blaring, and the driver completely unaware.

@David Richerby: As FreeMan says, motorists are often oblivious to both lights and sirens.  From my own experience, even when you do hear a siren, it's often difficult to determine just where it's coming from.  (It just gets your attention so you look for the flashing lights.)  The other issue is that people would have to recognize just what an airplane siren was.  Given that crashes are so infrequent, probably everyone would just stand around asking "What's that noise?"

They did design one plane with a siren to warn people on the ground.  The aircraft was called the "Stuka"
The pilot would diligently turn on the warning siren right before he nosed down and dove at 300 miles per hour to accurately release his bombs onto the people he was warning.
The warning siren terrorized the general public, so they stopped using it out of consideration for the bomber pilots, who didn't like getting shot down by the military employed to protect the public.

while most of this is true, the answer would benefit froma rephrasing to be less humoros and more factual, possibly with links to autoritative sources.

See also this question.


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What is the impact of one trailing edge rotary actuator failing?
I know aircraft commonly have rotary actuators to extend and retract the flaps.  I am not sure how many but I think I read two per flap on a 747. My question is what is the result if one actuator fails? I don't know if more then one needs to fail in order for a flap not to extend or retract.  I am mostly wondering if could cause an aircraft turn-back because somebody told me it could. However that does not seem right to me.  I thought the flaps are extended before take-off so that worst case scenario prior to flight is a minor flight delay to replace it.
I suppose if it failed just prior to landing that would be the other scenario and am not sure what the worst impact on a pilots ability to land would be (assuming one failed unit would prevent a flap extension?).
Any experienced pilot probably knows more then I do and any insights are welcome.

The 747 has two motors per flap group.  The primary means of moving them is through a hydraulic motor, while the second motor is a backup electric motor which is only used if the primary doesn't work correctly.
There are also two groups of flaps on each wing, and they are mechanically linked to the same flap group on the other wing so that they always extend at the same time.
You are correct about a failure on the ground.  The pilots would take the airplane back for maintenance before they departed.
In the unlikely event that both the primary and secondary motors failed, or if the flaps were to somehow become jammed and not extend once airborne, the flaps would not be able to do their job.  Since they wouldn't make the wing bigger or change it's shape to create more lift, the aircraft would be forced to land at a higher airspeed, which would cause it to use more runway.  This isn't a big deal if there is sufficient runway at their destination, but if not they would have to divert to a suitable airport.

+1 thanks, is helpful.  I am thinking your are right, there are probably hydraulic and electric sources of power, that power the many rotary actuators (I think I counted 32 for each wing 744). These probably use the electric or hydraulic power to provide high levels of torque, turning gears, that in turn, pull the chains that move each flap. When I am back at work I may have to confirm the details. In any case I think you helped me see the impact.  I suppose some kind of flaps disagree message would result if one flap did not move properly.

Yes, they have three FCU's (Flap Control Units) that command and monitor each system and provide warnings if they disagree, as well as automatically switch to the secondary system.  By the way, the title of your question asks about leading edge actuators but the body of the questions specifically mentions flaps, so my answer addresses trailing edge flaps.  The leading edge slats are slightly different, but have similar consequences.

there is an incident with a A320 experiencing a flap lockout, they successfully landed overspeed on the longest runway http://avherald.com/h?article=47380aba&opt=0


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Can seaplanes land on normal airfields or in a marsh or muddy area?
I know there are some amphibious planes which can land on both water and land but how different is the their landing in comparison to that of a normal small aircraft?
Also, if seaplanes needs to go into some marsh, will that work for them?

If the ground is soft and wet: Yes, no problem. Avoid any solid objects, though!

I suppose you mean without significant damages. Otherwise, the result is the same as landing without extending gear

@ManuH: You will be surprised how sturdy the bottom of a float or seaplane hull has to be. After all, when planing all the mass of the craft is supported by a very small area. Water is 800 times more dense than air, and as a rule of thumb the structure of a seaplane fuselage is 50% heavier than that of a comparable landplane.

A pure seaplane cannot land on a normal (land) airfield: The hull or floats would be badly damaged.
An amphibious aircraft can land on both water or a normal airfield (pavement, grass, gravel, etc.), because it has both wheels and floats, but with amphibious aircraft you're either operating as a seaplane (on water) or a landplane (on solid ground), and you would follow procedures appropriate to the type of operation you're conducting.

As I understand it amphibious aircraft would not be suited to landing in a "marsh" or "swamp": The water and mud would render the wheels ineffective (and possibly dangerous: If the wheels dig in to the mud the aircraft could flip over), and the dirt/land portions of the area would damage or destroy the floats/hull.
It may be possible to put the aircraft down in such an area, but it would be very unsafe, bordering on reckless, to do so in a non-emergency situation.

It also depends on where it's on floats or whether it's a flying boat.  The Grumman line of flying boats, like the Albatross, have retractable wheels. Also, terminology wise, it's amphibious floats

@rbp: Both flying boats and float planes can be amphibious and neither have to be. The large flying boats of early days were not, because at the time there were no runways they could use anyway. On the other hand float conversions of utility aircraft often are, because they want to land on lakes in the bush, but on airports in the cities.

Yes that was exactly my point.

Back in the early 1970s I belonged to a Civil Air Patrol (CAP) squadron that had a J-3 cub with an 85 horse engine on it. During the summer we would operate it on floats, during the winter on wheels. At the end of summer, we would land it on the grass alongside the runway at the Springfield, OR airport (no longer there, it's a big Walmart now) and replace the floats with wheels. In late spring, we'd replace the wheels with floats and take off from the grass.
The joke was that for takeoff you were supposed to line up all the cadets and have them pee in unison along the path the floats would take to aid in the takeoff. Actually, that wasn't necessary since western Oregon gets a lot of rain. Even with wet grass though, for the takeoff we'd get the initial movement by pushing, and we were always careful to ensure that the grass had nothing on the takeoff path that would damage the floats.
With the floats on, you could fly when the airspeed said 40 mph (yes, it was indicated in mph) which is about 35 knots. You could generally count on at least 5 knots of wind right down the runway when it was raining, so at 30 knots across the grass you were good to go.
You can go to YouTube and search "floatplane landings on grass" to see some examples of landing on grass. "Floatplane takeoffs on grass" will show some takeoffs, but a quick look showed using a dolly, which I think we did once or twice before my time with the group but then figured it was easier to just use the grass.

CAP = Combat air patrol?

@asawyer Civil Air Patrol

@TheGuywithTheHat That would make more sense. Thanks!

Seaplanes can land on land (pun intended) if the ground has a soft cover. This could be snow, tall grass and landing in a wet peat bog is also possible. However, any solid object close to the surface (logs, stones) will damage the hull.
Historic cases are the landings of Amundsen with a Dornier Wal on arctic ice or the landing of Gronau's Wal when it was transferred to the Museum in Munich (actually, this was the same aircraft). It was landed in winter on a snow-covered meadow close to the Isar river in central Munich.
This was in no small part possible due to the flat hull shape of Dornier flying boats. They were optimized with water tunnel studies for the heavy and inefficient engines of their time. Modern hulls have a keeled shape, where the bottom is v-shaped to reduce the load factor when planing in rough sea. Landing such a seaplane on land needs more snow and should not be attempted on grass.


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What causes hunting movement in helicopter rotors?
The blade of an helicopter rotor can have three hinges: pitch hinge, flapping hinge and lead-lag hinge.
Lead-lag (dragging): movement of a blade forward or aft in the plane rotation. Lead lag is facilitated by a lead-lag hinge in the rotor system or through rubber like bearings that allow individual rotor blades to move back and forth in their plane of rotation.
This helps balance the blade system and reduces vibration. The drag brace or drag damper resists the movement of the blade around its lead-lag hinge on a semi-rigid rotor system.
In the same plane, we have also the hunting, defined as the tendency of a blade to oscillate ahead of or behind a position which would be determined by centrifugal force alone.
Why should the centrifugal force alone determine a movement aft and behind the plane of rotation?

“aft” and “behind” are (near-)synonyms. Did you mean to repeat “ahead or behind” as in the quote?

The quoted text does not claim centrifugal force determines movement ahead or behind anything. It claims that there is a movement compared to what centrifugal force determines, or in other words that the movement is caused by something else than centrifugal force.

@JanHudec you are right in both comments. The first one was a lapsus, the second one was a misunderstanding.

Would someone please edit the question to clarify for those of us who aren't well versed in helicopter?

Lead lag is caused by the blades speeding up and slowing down as they flap up and down.
The blade on the advancing side experiences an airflow equal to it's speed plus the forward speed of the helicopter.  The blade on the retreating side experiences airflow equal to the speed of the blade minus the forward speed of the helicopter.  This causes dissymmetry of lift.
To counter this, the blades can flap up and down around the flapping hinges.  The blade on the advancing side flaps up, reducing the angle of attack and therefore the lift generated.  The blade on the retreating side flaps down, increasing the angle of attack and therefore increasing lift.
See this video at around 1:30 to see flapping in action.  This is a gyrocopter, but you can really see the blades flapping on this one at 0:39 and 1:17.
Due to conservation of momentum, the blade flapping up speeds up as it's centre of gravity moves inwards toward the rotor hub.  Since the rotor is turning at a constant speed, the blade must move forward around the lead/lag hinge.  In a similar way, the blade flapping down slows down so lags.
The blades will hunt forward and backwards from the neutral position in a sine wave as the rotor rotates.  Lead/lag dampers reduce the force of this hunting.
A variation of flapping hinges (independent hinges for each blade) is a teetering hinge on 2 blade helicopters where the hinge is connected to each blade.  If one blade rises, the other must fall and vice-versa.  The entire rotor disc "teeters" on top of the drive shaft.  This is known as a semi-rigid head and as far as I know, is used on all 2 blade helicopters.
In semi-rigid and rigid heads, the overall effect of the blades speeding up and slowing down cancels out in the complete cycle of rotation and other mechanisms are used to reduce the hunting loads.  Imagine a 4 blade rigid rotor.  2 blades are trying to speed up the rotor and 2 are trying to slow it down in equal amounts.
One serious side effect of lead/lag on fully articulated heads is ground resonance.  Since the blades can move forwards and backwards, it is possible for the blades to get closer together on one side than on the other, especially when the helicopter lands with a roll angle, so one gear hits the ground first.  This shifts the centre of balance away from the centre of rotation which can induce a wobble of the rotor head, which translates into a vertical "bounce" vibration at the landing gear. If conditions are right (or wrong, depending on your view point), the resonance can be amplified by the natural resonance frequency of the helicopters landing gear and can lead, if allowed to continue, to the destruction of the aircraft.
If you think that helicopter blades are quite rigid, think again.

But then... hunting and lead-lag are synonyms?

@GianniAlessandro: I believe they are, yes.

@GianniAlessandro Yes, because each blade moves backwards and forwards as it rotates, therefore hunting around the middle position.  Lead/lag, drag and hunting are synonyms.

@Simon upvoted. i think the answer would be improved by adding information about flapping versus teetering, as well as the downsides of lead-lag hinges in terms of ground resonance.

@rbp, thanks.  Done.

Teetering rotors are 'underslung' to maintain a constant center of mass during the flapping cycle. Lead-lag movements are not required, so long as the rotor is coned to a certain degree. Twin bladed tail rotors are delta hinged to provide lead lag. Augusta helicopters have pre-coned tail rotors and are both underslung and delta.


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Can you do your PPL solo time in an ultralight?
I've been thinking of getting an ultralight as a low cost way to pursue flying.  And I've been wondering, when my instructor finally signs me off for a solo flight, am I allowed to do that in an ultralight?  And, if so, is there equipment I would be required to have that isn't standard on an ultralight?

Ultralights in the USA are not classified as aircraft and don't need a pilot's license. That would mean 1. probably no and 2. there wouldn't be any point if you want to fly ultralights.

@DJClayworth -- actually, the FAA does consider ultralight to be "aircraft".  But of course you are right that you don't need a pilot's license to fly them.  See https://aviation.stackexchange.com/questions/56294/in-the-united-states-are-ultralights-legally-considered-aircraft/56295#56295

@quiet flyer 14 CFR 103 describes ultralights as vehicles, not aircraft.

@RetiredATC-- re "14 CFR 103 describes ultralights as vehicles, not aircraft." -- see this https://aviation.stackexchange.com/questions/56294/in-the-united-states-are-ultralights-legally-considered-aircraft/56295#56295

Nope.
Your solo time must be done in the category and class of aircraft for which you are seeking a pilot certificate (the FAA doesn't come out and say it in those words, but that's what the "aeronautical experience" requirements basically boil down to). You must also pass a pre-solo knowledge exam and receive instruction in the particular make and model of aircraft you will be solo-ing in (the second of which is impossible in an ultralight: You cannot receive dual instruction in that aircraft as by regulation it can only have one seat).

As you don't need a pilot certificate to fly an ultralight you could just get one, get some basic instruction on flying it (from someone who has flown them before), and go fly. Some ultralights are pretty fine basic aircraft thanks to modern materials and construction techniques.
Your private pilot training & solo experience would be helpful in flying certain types of ultralight aircraft, but it's not required as long as you abide by the regulations applicable to ultralights.
Similarly experience in the more "airplane-like" ultralights may help you out in the rest of your private pilot training, but that experience isn't required (and not really "loggable" toward your training, through you can put it in your logbook if you wish -- just log the time as "Ultralight Flying" or something similar.)

Any chance you could cite or inline the regulation you are referencing in the first part of your answer?

@JayCarr 14 CFR 61.109(a)(5) "10 hours of solo flight time in a single-engine airplane, consisting of at least..."

@casey Ultralights have a single engine?  So wouldn't this imply that you could use an ultralight if "having a single engine" is the only litmus test?

@JayCarr and for the pre-solo requirements he mentions, see 14 CFR 61.87.

@JayCarr an ultralight is not an "airplane" according to the FAA - it's not even an "aircraft", but rather an "ultralight vehicle" (this is kind of like how the tomato is "legislatively a vegetable": It looks like an aircraft, it flies like an aircraft, so it must be...an "ultralight vehicle"). If your ultralight is registered as an "Experimental: Amateur-Built" aircraft (with an N number) that might change things though.

@voretaq7 Ah, I see :).  Any chance you could inline those links or the text or something?  I'd feel better about accepting the answer if you did that...

@voretaq7 -- re "an ultralight ... according to the FAA ... it's not even an "aircraft"" -- for a different view see https://aviation.stackexchange.com/questions/56294/in-the-united-states-are-ultralights-legally-considered-aircraft/56295#56295

Under 14 CFR § 61.51 (j) Aircraft requirements for logging flight time, the aircraft must have an airworthiness certificate, be registered in the US or with an ICAO member state; or be a military or law enforcement aircraft.
FAR 103 vehicles, by definition, do not have airworthiness certificates and can not be registered.
So while I agree that some FAR 103 vehicles are literally airplanes; for the purpose of logging flight time, by law they are not considered unless you somehow convince a police department or branch of the military to employ you to fly one.

This is possible in one situation: if you were to build an ultralight kit and register the plane as a homebuilt. Then it would get an N-number and be an aircraft. However, if you were going to build, it probably makes more sense to upgrade to the LSA level, even with an ultralight-style plane.

If it were N-numbered, it would no longer be an ultralight as far as the FAA is concerned.     I suspect you are aware of that; answer might benefit from including that.  (Still might meet the OP's intent of a low-cost way to fly.)  However, saying that getting an N-number makes the difference as to whether it is considered "an aircraft" reflects a common understanding, but is not really accurate-- for a different view see https://aviation.stackexchange.com/questions/56294/in-the-united-states-are-ultralights-legally-considered-aircraft/56295#56295.

Yes, this is why I used the terms homebuild and ultralight-style.